In the luggage or bag field, there are generally two basic types of construction: (1) soft bags, in which the outer walls are made of a flexible material such as leather, vinyl, fabric, etc., and (2) hard bags, in which the outer walls are made of a hard plastic material such as polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP), etc. Soft bags, although they can be agreeable in appearance and light in weight, often do not afford adequate protection to the contents against external forces. For greater resistance to deformation, rigid internal frames have been provided in soft bags to maintain the shape of the bag. Such rigid internal frames, however, add significantly to manufacturing costs and also increase weight.
Hard bags have the advantage of resistance to deformation by external forces, which affords greater protection to the contents against damage. Such bags, however, tend to be less attractive in appearance or to the touch. They also tend to be heavier. Additionally, hard bags often require more complex manufacturing techniques, including the use of expensive molding techniques that require complex and expensive equipment, multiple heating and cooling steps, trimming steps, and cleaning steps to produce the luggage body. The amount of time the molding equipment is utilized to produce a piece of luggage is a significant factor in the cost of manufacturing that piece of luggage. Thus, the manufacture of hard bags can be expensive and time consuming compared to soft bags.
Items of luggage that attempt to combine certain features of hard and soft bags are described in U.S. Pat. No. 6,936,127 to Fenton et al. and U.S. Pat. No. 6,604,617 to Davis et al., the disclosures of which are incorporated in their entireties by reference herein. Nevertheless, there remains a need for a lightweight piece of luggage that has greater strength to resist deformation by external forces and can be produced with relatively simple and inexpensive manufacturing techniques.